Frequency-sweep experimental method for predicting noise of power capacitor

摘要

A frequency-sweep experimental method for predicting noise of a power capacitor, comprises steps of: (1) loading the capacitor with a sine voltage excitation with a loading frequency value of ½ to 50 times of a power frequency in sequence, at an increase of half of the power frequency for each time, and measuring vibration velocity at various points on a case of the capacitor; (2) under each loading frequency, dividing vibration velocity by a square of each voltage applied; (3) calculating frequency spectrum of a square of the voltage of the capacitor according to the voltage and a current of the capacitor; (4) multiplying the frequency spectrum of the square of the voltage of the capacitor by the electromechanical vibration frequency response function value of the capacitor to obtain a vibration velocity spectrum of the case of the capacitor; (5) calculating acoustical power of the noise.